Cassandra,
I don't think there is a "best" rooting method. Over time and with experience, any method you use and tweak will be as good (close enough) as any other. I've tried the method you referenced. FOR ME, part of the method (using the baggie) works well. For the remainder, I'm going in a different direction. Others have had very good luck with the method. Like I said, think of it as a springboard and see where it works and where it needs some work for you.
Also, if you can get 3 or more cuttings it improves your chances of having a successful strike. Or if the tree is nearby, ask if you can air-layer the limb rather than cut it.
Good luck,
~james